Wheel bearings / axles - Help with sizes..?

I recently bought a specialized tri spoke. It was a rear, but I wanted to ride it as a front.

I thought I'd be able to change the spacers and use nuts instead of a skewer to fit it to my forks. Annoyingly the axle thread, I was told, is imperial, so finding nuts to fit was hard work, but I found some. When I went to put the wheel in the axle didn't quite fit into the dropouts(!) - so I persuaded it to go in.. with a hammer.

I am not really happy with having to use a hammer to take my front wheel off and on. :(

So, I recently took appart the hub/bearings/axle on my old front wheel as it had, what looked like, the same size bearings. I was hoping I could then use this old axle.
I was wrong, the bearings are a different size and the axle has a different width to fit to the inner bearing case. !!

I need either a front axle that will fit the bearings that are the tri spoke, OR a new set of bearings that will fit the tri spoke and a standard front axle. Can anyone suggest what would be easiest?

So, the question I need answered is:

**What different sizes are available for sealed bearings (for hubs)? **

...and where can I get a matching axle(s)?